Automatic speed limiting mechanism for automotive vehicles



I. COWLES March 12, 1940.

Filed Feb. 1l, 1938 i? (IOW/es l? .L4

s` nu AUTOMATIC SPEED LIMITING MECHANISM FOR AUTOMOTIVE VEHICLESPatented Mar. 12, 1940 AUTOMATIC SPEED LIMITING MECHANISM FOR AUTOMOTIVE`VEHICLES Irving Cowles, Detroit,

Cowles and Rudolph Mich., assigner to said W. Lotz, Chicago, Dl., as

successor cotrustees of` Utility Patents Trust Application February 11,1938Serial No. 190,111

7 Claims.

The essential object of the present invention is to provide simple,cheapand efficient means for limiting the speed of an automotive vehicleWithout limiting the engine speed of the same in order that the enginemay operate at maximum speed when the change-speed gear setof` thevehicle is set for low speed vehicle travel as, for example, inascending steep grades, traveling through mud, sand, and the like.

A further object of the invention is to provide a device of thecharacter designated which constitutes a substitute for the rod commonlyused to connect the buttery valve of the carbureter With the acceleratorplunger of the vehicle so that the device may be installed relativelyeasily in' existing vehicles, the only other change required being theinstallation of automatic electric circuit control means for the saiddevice.

Obviously, under certain conditions of travel, such as climbing steepand long grades under heavy loads, as in the case of `Inotorpropelledtrucks, it is essential that `the `engine should operate at full speedunder low speed gear conditions Whereas safe driving under heavy traicand other road conditions renders wise the precaution of limiting themaximum speed at which the vehicle may travel. 'I'he present inventionis designed to meet all of the necessary conditions incident to motorvehicle travel to promote safety without reducing maximum powerdevelopment of the engine for lpurposes other than the attainment ofhigher speed travel than the promotion of reasonable safety dictates.

To this end and in contrast to prior art disclosures known to me, thepresent invention consists broadly in providing a vehicle speed limitingmeans operatively associated directly or indirectlywith andcontrolledfby `the R. P. M; of one of the vehicle wheels.

SuitableI embodiments, of the inventionare illustrated in theaccompanying drawing, where- 1n: f

Fig. 1 is a central longitudinal sectionalview of an elongatable deviceconstructed in accordance with the invention.

Fig. 2 is a transverse sectional view of the same on an enlarged scaletaken on the line 2-2 of Fig'. 1.

Fig. 3 is a view similar to Fig. 1 showing a contractible deviceconstructed `in accordance with the invention.

Fig. 4 is a perspective view of the pistons of the devices shown inFigs. 1 and 2.

Fig. 5 is a diagrammatic view oi a centrifugal governor actuated circuitcontrol device adapted to be employed in connection with the structuresof Figs. 1. and 2. y

Fig. 6 is a diagrammatic view showing the device of Fig. 1 connectedwith the accelerator lever and the engine control valve of an automotivevehicle.

The respective devices of Figs. l and 3 talle the place of rodsconnecting the accelerator plunger of an automotive vehicle with thebutteriiy valve of the carburetor, the terminal rods I and 2,respectively, of said devices being suitably attached to or connectedwith the accelerator" plunger or a part actuated thereby. The lateralprojections 3 and d of said respective devices are adapted to beattached to the cranks of the stems of the butterfly valves of thecarbureters, thedevice of Fig. 1 being adapted to be attached to thebutteriiy valve which is closed by moving the projection 3 to the right,whereas, in the structure of Fig. 3 the projection@ is attached to the`crank of the stem of a butterfly valve which is closed by moving theprojection ll to the left.

In the instance ofFig. 1 the device comprises a hollow cylindrical lefthand end portion 5 which is adapted to receive the spring urged armature6 of the solenoid i Whichis mounted between the ends oi" the generallytubular structure which includes the cylinder il having fluid tightconnection with the spool of the solenoid l and which is equipped with afluid-tight closure head `9 through which the rod It! equipped with aprojection extends, a packing gland II being mounted in the head 9 toassure a fluid-tight joint with the said rod I0.

Mounted at the inner Iend of the rod Il] is a piston I2 which isconnected with a rod I3 secured to the armature Il of the solenoid. Thelight compression spring I/-I mounted in the cylinder 8 bears againstthe head d and the piston i I2 to hold the latter normally at the innerlimit of its movement as shown in Fig. 1. p

The piston I2 is equipped with one or more bleed openings I5 throughwhich air is adapted to pass from the cylinder into the space at theleft hand end of the piston I2 as the latter moves toward the head 9,the said cylinder 8 constituting the substantial equivalent of a dashpot.

In Fig. 5 there is shown a centrifugal governor which may be mountedupon any one of the shafts driven from the change-speed gear set of thevehicle. The said governor includes a collar I6 rigid with-the shaft Iland which is connected vby means of links I8 in a Well-known mannerwith. the spheres or balls I9, the latter` being connected by means oflinks 20 with the collar 2| which is suitably connected with thecylindrical rack bar sleeve 22 slidable, and also preferably rotatableon said shaft Il'. The rack 22 meshes with the spur-gear pinion 23,mounted upon a xed pivot which carries the bridge member 24 of anelectric switch which includes also the respective terminals 25 and 2S,the latter being connected by means of wire 21 with the source ofcurrent 28, which may be the magneto of the power plant, the latterbeing also connected by wire 29 with one terminal of the solenoid 'l'.The switch terminal 25 isconnected by means of wire 30 with the otherterminal of the solenoid '1.

By means of the spring 3l, the rack bar 22 is normally held in aposition wherein the switch member 24 is out of contact with theterminals 25 and 26. The governor may be so adjusted, as, for example,by means of an adjusting nut 32 on the shaft Il, disposed between thecollar l5 and the spring 3l, for example, that as soon as the vehiclespeed exceeds fifty M. P. H., the rack-bar will be moved responsively tothe action of the governor to a position wherein the circuit through thesolenoid 'l is closed. When this occurs the armature 5 will be throwntoward the right against the action of the spring I4, thus causing thebutterfly valve of the carburetorA to close gradkit ually, due to thedash pot action above referred to, thereby obviously effecting adecrease in engine speed.

However, if the change speed gear set is operating to cause the vehicleto travel more slowly without reducing engine speed, then obviously, themaximum engine speed may be obtained to exert maximum power on therunning gear of the vehicle without in any manner affecting theoperation of the device to limit such engine speed.

The device of Fig. 3 operates in exactly the same manner as the deviceof Fig. 1 except that the piston l2!) is normally disposed at the outeror right hand end portion of the cylinder and is moved to the left byoperation of the solenoid armature Bil when the circuit through thesolenoid 1B is closed, thereby also closing the butterfly valve of thecarburetor to reduce engine speed.

An exemplary connection of the device of Fig. 1 is illustrateddiagrammatically in Fig. 6 wherein the rod l is connected with therocking lever 33 mounted upon the front lower face of the floor board 34or an automotive vehicle for actuation by the reciprocable plunger 35projecting through said iloor board. The rod 3 is connected with theengine speed control valve actuating lever 36 so that upon pressing thedrivers foot against the plunger 35 the device of Fig. 1 will be movedto the left and, in this instance, the valve controlled by the lever 36will be swung to further open position to increase engine speed, Thegovernor of Fig. 5 is disposed in the casing 31 at the left side of thechange-speed gear casing 38 and controls the circuit through thesolenoid l for effecting closure of said circuit when the shaft 39, towhich the said governor is geared, attains the predetermined maximumspeed for which the governor is adjusted.

The device of the present invention is obviously very simple andoperates efliciently to control vehicle speed without in any manneraffecting engine speed when the engine is geared to drive the vehicle atlow speed, but with maximum power. as aforesaid.l

It is very important also that the speed of operation of the pistonresponsively to both the electric and spring actuations thereof shouldbe relatively slow in order that the variations in engine speed may notbe too sudden, as that would be dangerous under certain road conditions,as on wet or icy pavements on the one hand, and undue shocks or stresseson the engine and gearing on the other.

While the invention is illustrated and described as applied toautomotive vehicles, it may be equally well adapted for other powerinstallations wherein the speed control should be such as not to limitmaximum engine speed and power generation in order to carry overload onthe engine driven mechanism as, for example, in hoisting and excavatingmachinery.

I claim as my invention:

1. A device for the purpose set forth comprising a tubular casing, meansfor connecting the same at one end with the accelerator mechanism of thepower plant of an automotive vehicle, a. reciprocable piston in saidcasing, a spring for maintaining said piston normally at one limit ofits movement, electrically responsive means associated with said pistonfor actuating'the same counter to said spring, a piston rod connected tosaid piston and adapted for connection with means for controlling engineoperation independently of said accelerator mechanism, a normally openelectric circuit through said electrically responsive means, andautomatic means for opening and closing said circuit operativelyconnected with and actuated by the running gear of the vehicle.

2. A device lor the purpose set forth comprising a tubular casing, meansfor connecting the same at one end with the accelerator mechanism of thepower plant of an automotive vehicle, a reciprocable piston in saidcasing, a spring for maintaining said piston normally at one limit ofits movement, a solenoid having its armature connected with said pistonfor actuating the latter counter to said spring, a piston rod connectedto said piston and adapted for connection with means for controllingengine operation independently of said accelerator mechanism, a normallyopen circuit through said solenoid, a switch controlling said circuit,vand a mechanism actuated by the running gear of the vehicle foractuating said switch to close the said circuit as the vehicle speedexceeds a predetermined maximum and reopening said circuit as thevehicle speed decreases to the said predetermined maximum.

3. A device for the purpose set forth comprising a tubular casing, meansfor connecting the same at one end with the accelerator mechanism of thepower plant of an automotive vehicle, a reciprocable piston in saidcasing, a spring for maintaining said piston normally at one limit ofits movement. electrically responsive means associated with said pistonfor actuating the same counter to said spring, a piston rod connected tosaidpiston and adapted for connection with means for controlling engineoperation independently of said accelerator mechanism, a normally openelectric circuit through said electrically responsive means, andautomatic means forv opening and closing said circuit operativelyconnected with and actuated by the running gear of the vehicle and meansassociated with said piston for controlling the speed of its movements.

4. In an internal combustion engine-driven vehicle, an engine speedcontrol valve, an accelerator lever, a cylinder and piston reciprocablerelatively to each other interposed between said lever and said valveand constituting a variable length connection between them, a spring forCII normally maintaining" the said piston at one limit of its movementrelatively to said cylinder, said piston including an armature and saidcylinder including a solenoid, a normally open circuit through saidsolenoid operatively connected with and controlled by the speed oitravel of the vehicle and, vvhenclosed,` actuating said piston againstthe action of said spring for moving said valve to an engine slowingposition.

5. In an internal combustion engine-driven vehicle, an engine speedcontrol valve, an accelerator lever, a cylinder and piston reciprocablerelatively to each other interposed between said lever and said valveand constituting a variable length connection between them, a spring fornormally maintaining the said piston at one limit of its movementrelatively to said cylinder, said piston including an armature and saidcylinder including a solenoid, a normally open circuit throughsaidsolenoid operatively connected with and controlled by the speed ortravel of the vehicle and, when closed, actuating said piston againstthe action of said spring for moving said valve to an engine slowingposition, and means associated with said piston and cylinder anddisposed within the latter for yieldingly resisting relativereciprocable movements of saidpiston and cylinder. l

6.- In an internal combustion engine-driven vehicle, the combinationwith a engine speed oontrol valve, an accelerator lever, and a governorconnected with the running gear for actuation thereby, of a cylinderequipped at one end with a solenoid axially aligned therewith, a pistonequipped with a rod and an armature rigid therewith reciprocablyvmounted within the cylinder, a

spring acting to maintain the piston normally at one limit of itsmovement, and an electric circuit through said solenoid controlled bysaid governor, said cylinder and piston rod interposed between theaccelerator lever and said rvalve with one thereof connected to saidlever and the other thereof with said valve, said circuit being adaptedto be closed automatically by said governor as the vehicle speedattainsy a predetermined maximum to effect actuation of said pistonagainst said spring for moving said valve to engine speed reducingposition. g

'7. In an internal combustion engine-driven vehicle, the combinationwith an engine speed control valve, and accelerator lever,`and agovernor connected with the running gear for actuation thereby, of acylinder equipped at one end with a Solenoidaxially aligned therewith, apiston equipped with a rod and an armature rigid therewith reciprocablymounted within the cylinder, a spring acting to maintain the pistonnormally at one limit'of its movement, means for yieldingly resistingmovement of the piston relatively to the cylinder, and an electriccircuit through said solenoid controlled `by said governor, saidcylinder and piston rod interposed between the accelerator lever andsaid valve with one thereof connected to said lever andthe other thereofwith said valve, said circuit adapted to be closed automatically by saidgovernor as the vehicle speed attains a predetermined maximum to effectactuation of `said piston against said spring for moving said valve toengine speed reducing position.

IRVING COWLES.

